Benzylidene bisphenol acylate exhaust emission reducing additive



United States Patent US. Cl. 260395 9 Claims ABSTRACT OF THE DISCLOSURE Monoand dialkanoates, aralkanoates and benzoates of benzylidenebisphenols reduce combustion chamber deposit formation and exhaust hydrocarbon emission internal combustion engines.

BACKGROUND Hydrocarbons are reported to react with ozone in the atmosphere, forming irritants. When the level of these irritants becomes high enough, there results what is commonly referred to as photochemical smog. Thus, a need exists for a method to reduce the amount of hydrocarbons introduced into the atmosphere from various sources. One source is the exhaust gas of internal combustion engines. Previous means of reducing exhaust emissions have concentrated on the secondary oxidation of the unburned exhaust products employing either catalytic oxidizing methods or direct flame oxidation in the exhaust system. If the amount of unburned hydrocarbons initially in the exhaust can be reduced, the need for secondary oxidation is diminished. Most previous attempts to reduce the initial hydrocarbon content of the exhaust gas have concentrated on mechanical means such as improved carburetion. The present invention provides a method of reducing exhaust emission and engine deposits through the use of an exhaust emission reducing additive.

SUMMARY This invention relates to a method of reducing the combustion chamber deposit formation and the increase in the level of exhaust hydrocarbon emission normally observed during the life of an internal combustion engine. A new internal combustion engine having an acceptable exhaust hydrocarbon level often exhibits an increase in this initial level during use, giving rise to an unacceptable emission level. The present invention provides a simple method of decreasing this increase in emission level by as much as 60 percent. This can be accomplished by merely adding a small amount of an emission control additive to the fuel or lubricant used in the engine or otherwise providing means for getting the additive into the combustion zone.

An object of this invention is to provide a means of reducing the deposits formed in an internal combustion engine. A further object is to reduce the increase in exhaust hydrocarbon emission normally observed during the life of an internal combustion engine.

These and other objects are accomplished by providing an exhaust emission reducing compound having the wherein R and R are independently selected from the group consisting of alkyl radicals containing from 1 to about 20 carbon atoms, aralkyl radicals containing from 7 to about 20 carbon atoms, aryl radicals containing from 6 to about 20 carbon atoms and cycloalkyl radicals containing from 5 to about 20 carbon atoms; R R R and R are independently selected from the group consisting of hydrogen, alkyl radicals containing from 1 to about 20 carbon atoms, aralkyl radicals containing from 7 to about 20 carbon atoms, aryl radicals containing from 6 to about 20 carbon atoms and cycloalkyl radicals containing from 5 to about 20 carbon atoms, R; is selected from the group consisting of hydrogen, alkyl radicals containing from 1 to about 20 carbon atoms, aralkyl radicals containing from 7 to about 20 carbon atoms, cycloalkyl radicals containing from 5 to about 20 carbon atoms, and aryl radicals containing from 6 to about 20 carbon atoms, and Z is selected from the group consisting of hydrogen and radicals having the formula:

wherein R is selected from the same group previously described for this radical.

Some examples of these compounds are:

4, 4-benzylidenebis 6-tert-butyl-o-cresol diacetate 2,2'-benzylidenebis(4,6-dimethylphenol) dibutyrate 2,2- p-sec-eicosyl-benzylidene bis (4-seceicosyl-6- methylphenol distearate 2,6ditertbutyl-6-methyl-4,2'-benzylidenediphenol l'-forrnate 4,4'- 3 ,5 -di-tert-butyl-benzylidene bis o-secamylphenol dioleate 4,4- (p-sec-nonyl-benzylidene bis 2,6-dimethylphenol dibenzoate 5, 6-dimethyl-2-sec-butyl-2'-isopropyl-4,4'-benzylidene diphenol 1-acetate-llaurate 2,6-dimethyl-2'-phenyl-4,4'-benzylidenediphenol 1-b utyrate 4,4- (p-methyl-benzylidene) bis [2- (a-methylbenzyl) -5- methyl phenol] distearate 4,4-benzylidenebis 2,6-dicyclohexylphenol) dibutyrate 2,5 -di-tertbutyl-2- a-rnethylbenzyl) -5 '-methyl-4,4- 3

methyl-S-phenylbenzylidene diphenol diacetate 2,4'-benzylidenebis 6-tert-octylphenol diacetate.

In a preferred embodiment of this invention, R and R in Formula I are bonded to the carbon atom of their respective benzene nuclei at the position ortho with respect to the carbon atom in said benzene nuclei bonded to oxygen and are selected from the group consisting of alkyl radicals containing from 1 to 20 carbon atoms, aralkyl radicals containing from 7 to 20 carbon atoms and cycloalkyl radicals containing from 5 to 20 carbon atoms. These compounds have the following formula, in which R R ,R R R and Z are selected from the same groups defined for Formula I and R and R are selected from the above described group.

Some examples of these preferred embodiments are:

2,6-di(a-methylbenzyl)-2',6-dimethyl 4,4 benzylidene diphenol l-acetate 2,6-diethyl-2',6'-di-n-propyl 4,4 (p-nonylbenzylidene) diphenol l-acetate 1-butyrate 2,6-di-tert-butyl-2',6'-dimethyl 4,4'-benzylidene diphenol diacetate 2,2,6-trimethyl-6-tert-octyl-4,4 benzylidene diphenol dioleate.

In a more preferred embodiment the additives have Formula II and R and R are selected from the group consisting of alpha-branched alkyl radicals containing 3 to 20 carbon atoms, alpha-branched aralkyl radicals containing 8 to 20 carbon atoms and cycloalkyl radical containing 6 to 20 carbon atoms; R and R are selected from the group consisting of alkyl radicals containing 1 to 20 carbon atoms, cycloalkyl radicals containing 6 to 20 carbon atoms and aralkyl radicals containing 7 to 20 carbon atoms; R and R are hydrogen; Z is a radical having the formula:

it -C--R7 and R is an alkyl radical containing from 1 to about carbon atoms. Examples of this embodiment are:

4,4-benzylidenebis 6-tert-butyl-o-cresol diacetate 4,4'-benzylidenebis(2,6-di-sec-butylphenol)dibutyrate 4,4'-benzylidenebis 2,6-di-tert-b utylphenol dibutyrate 4,4'-benzylidenebis 2, 6di-tert-butylphenol diacetate 4,4-benzylidenebis(2,6di-tert-butylphenol)dihexoate 4,4-benzylidenebis 2,6-di-tert-butylphenol distearate 2,6-di-tert-butyl 2,6' diisopropyl 4,4 benzylidenediphenol dihexoate 4,4'-benzylidenebis 6- u-methylbenzyl -o-cresol dilaurate 4,4-benzylidenebis 2,6-di-sec-eicosylphenol dioleate 4,4'-benzylidenebis(6-tert-octyl-o-cresol)distearate.

The most preferred additive is 4,4'-benzylidenebis(2,6- di-tert-butyl phenol diacetate.

The additives are readily made by acylation of a benzylidenebisphenol. The benzylidenebisphenols are readily prepared by the reaction of the appropriate phenol with a benzaldehyde in a solvent using an acid or base catalyst. A suitable process is described by Filbey et al. in US. 2,807,653. The following example will serve to illustrate a method of making the emission control additives of this invention. All parts are parts by weight unless otherwise stated.

EXAMPLE 1 Preparation of 4,4'-benzylidenebis-(2,6-di-tertbutylphenol) In a reaction vessel equipped with stirrer, condenser, thermometer and reagent introducing means was placed 6.6 parts of potassium hydroxide dissolved in 400 parts of isopropanol. To this solution under a nitrogen atmosphere was added 206 parts of 2,6-di-tert-butylphenol and 53 part of benzaldeyhde. Towards the end of the addition solids began to appear in the reaction vessel. After stirring for 2 hours at 40 C., the solids were filtered off to give a good yield of 4,4'-benzylidenebis(2,6-di-tert-butylphenol).

Conversion to the diacetate To a reaction vessel equipped with stirrer, thermometer and cooling means was added 340 parts of ethyl acetate, 21.6 parts of acetic anhydride and 6 parts of 76 percent perchloric acid. The mixture was allowed to tand minutes at room temperature and then, while stirring, it 'was cooled to 0 C. An additional 110 parts of acetic anhydride was added and the mixture stirred at 0-5 C. for one hour.

In a second reaction vessel was placed 167 parts of 4,4 benzylidenebis(2,6-di-tert-butylphenol) and the above acylating solution was added to it over a 30 minute period. At first, the solids dissolved, but after stirring an hour, a precipitate formed. Then 200 parts of water were added followed by 900 parts of a 75 percent aqueous pyridine solution. After stirring 30 minutes the mixture was neutralized with percent sodium hydroxide to a pH of about 8. The mixture was further diluted with 7000 parts of water and the solid product removed by filtration. The yield was 190 parts, melting at 179182 C. After recrystallization from ethanol the melting point was 180- 182 C. Infrared confirmed the identity of the compound as 4,4'-benzylidenebis(2,6-di-tert-butylp-henol) diacetate.

The above procedures are generally applicable to the preparation of a wide variety of benzylidenebisphenol acylates. Further discussion of a suitable method of acylating phenolic hydroxyl radicals is published in Analytical Chemistry, 32, 987 (1960). Other methods of acylating hydroxy groups using the appropriate acid, acid anhydride or acid chloride are well known in the art and these can be advantageously used to prepare the acylated derivatives of benzylidenebisphenols.

The acylation process may be carried out on a mixture of benzylidenebisphenols resulting in a mixture containing a substantial amount of benzylidenebisphenol acylates. The preferred method of making these mixtures is to merely alkylate the phenol using Well-known methods, forming mixtures of mono-, diand trisubstituted phenols. Preferably, the mixtures are predominantly disubstituted phenol. These mixtures are then reacted with benzaldehyde in the presence of an acid or base catalyst, forming a mixture containing a substantial amount of benzylidenebisphenols. Following this, the mixture is acylated so that a substantial amount of the phenolic hydroxyl radicals are acylated resulting in a reaction product containing a substantial amount of a benzylidene-bis(hydrocarbylphenol)acylate. The following example will serve to illustrate this embodiment of the invention.

EXAMPLE 2 In a reaction vessel is placed 940 parts of phenol and 20 parts of phosphoric acid. The mixture is warmed to C., while stirring, and 112 parts of isobutylene is added beneath the liquid surface over a period of one hour. Following this, the reaction mass is washed, yielding a mixture containing predominantly dibutylated phenols together with some monoand tri-butylated phenol. To the mixture of phenols is added 2000 parts of isopropanol and 25 parts of potassium hydroxide. The mixture is heated to reflux and 550 parts of benzaldehyde is added over a one hour period. The reaction mixture is stirred at reflux one hour and then cooled to room temperature, and 1000 parts of water is added, causing the benzylidenebis(butylated phenol) mixture to precipitate. The aqueous phase is removed and the residue heated to 100 C. at 20 mm. Hg to remove residual Water. Then, 2000 parts of trichloroethylene and 100 parts of anhydrous zinc chloride is added. Following this, 1300 parts of n-butyrylchloride are added over a 30 minute period at 50-60" C. The temperature is raised to reflux and, after one hour, the mixture is cooled to room temperature and washed with water. The trichloroethylene is distilled off leaving a resinous product which contains a substantial amount of benzylidenebis(butylated phenol) monoand di-n-butyrate within the scope of this invention.

EXAMPLE 3 Alkylation of phenol with isobutylene is carried out following the procedure of Ecke et al., US. 2,831,898. The reaction product consists essentially of percent 2,6-di-tert-butylphenol, 15 percent o-tert-butylphenol, 7 percent 2,4,6-tri-tert-butylphenol, and 3 percent other isomers. To another reaction vessel equipped with stirrer. thermometer and heating means is placed 2000 parts of isopropanol, 18 parts of potassium hydroxide and 1000 parts of the above butylated phenol mixture. There is then added over a 30 minute period 541 parts of benzaldehyde, during which time the temperature is raised to 75 C. The mixture is stirred at 75 C. for 2 hours. Following this, 1000 parts of water are added and the aqueous alcohol phase removed. Isopropanol, water and unreacted benzaldehyde remaining in the product are distilled out by heating the product to 100 C. and reducing the pressure to 20 mm. Hg. The resulting product is a mixture consisting substantially of benzylidenebis (monoand dibutylphenol). This mixture is acetylated employing the general procedure of Example 1. The benzy1idenebis(butylated phenol) mixture is placed in a reaction vessel fitted With a stirrer and thermometer. A solution of 5100 parts of ethylacetate, 1980 parts of acetic anhydride and 90 parts of 76 percent perchloric acid is added to it While stirring at 20-30 C.,'over a period of 4 hours. Stirring is continued an additional hour, during which time the temperature is raised to 50 C. It is stirred at 50 C. for an hour and then cooled to room temperature. It is diluted with 3000 parts of water and neutralized to a pH of about 8 with sodium hydroxide. The aqueous layer is removed and the remaining product water washed until the ethylacetate has been substantially removed. The resultant product is a mixture of acetylated benzylidenephenol products containing a substantial amount of benzylidenebis,(monoand di-tert-butylphenol)diacetates, previously described as within the scope of the present invention.

The additives of this invention can be used to reduce emissions and combustion chamber deposits resulting from the use of a broad range of liquid hydrocarbon fuels including both spark ignition and diesel fuels. It is especially useful in gasoline used in spark ignition engines. These liquid hydrocarbon fuels have a boiling range of from about 95 to about 400 F. and contain aliphatic, aromatic, olefinic and naphthenic hydrocarbons. The hydrocarbon fuels may contain other materials frequently used in such fuels. For example, the fuels may contain antiknock agents such as tetraethyllead, tetramethyllead, triethylmethyllead, diethyldimethyllead, trimethylethyllead, tetravinyllead, triethylvinyllead, diethyldivinyllead, trivinylethyllead, ferrocene, methyl ferrocene, iron carbonyl, methylcyclopentadienyl manganese tricarbonyl, methylcyclopentadienyl nickel nitrosyl, N,N,-dimethylaniline, and the like. When metallic antiknock agents are employed, the fuels generally contain a scavenging agent. A particularly useful scavenging agent when lead alkyls are employed are the halohydrocarbons such as ethylenedichloride, ethylenedibromide, and the like. An especially useful fuel in this invention is a fuel containing from 0.5 to 6 grams of lead per gallon as tetraalkyllead and from 1.5 to 2.5 gram atoms of chlorine as a chlorohydrocarbon per gram atom of lead and from 0.5 to 1.5 gram atoms of bromine as a bromohydrocarbon per gram atom of lead. Preferred tetraalkyllead antiknocks are tetraethyl lead and tetramethyl lead. The most preferred chlorohydrocarbon is ethylenedichloride, and the most preferred bromohydrocarbon is ethylenedibromide.

It is often desirable to include an induction aid in th gasoline compositions containing the benzylidene bisphenol acylates. This is because some of the additives are high molecular weight, and, with a normal vaporization type carburetor, induct into the combustion chamber with difiiculty. This problem is not encountered in diesel engines or fuel injected spark ignited engines. Suitable induction aids are solvents boiling in the range of from about 300- 500 F. such as kerosene, alkylated aromatics, for exam ple, isopropyl benzene, diethyl benzene, and the like; ketones boiling from 300500 F. such as cyclohexanone, ethylcyclohexanone, ethyl-n-butyl ketone, diisobutyl ketone, and the like; ethers boiling in the 300500 F. range such as diethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, and the like; ether alcohols such as ethylene glycol monoisobutyl ether, ethylene glycol rnono-n'butyl ether; esters such as isoamyl propionate, cyclohexyl acetate, furfuryl acetate, and the like. Of the foregoing examples, the preferred induction aids are kerosenes boiling from 300 to 500 F.

The amount of induction aid employed varies from none to about 5 percent depending upon the ease of inductibility and the carburetor design. When an aid is used, a preferred concentration is from 0.1 to 5 percent. A more preferred range is from about 0.2 to 1 percent.

The fuels can also contain deposit modifying agents such as phosphorus-containing additives, for example, tricresylphosphate, cresyldiphenylphosphate, trimet-hylphosphate, dimethylcresylphosphate, tris(ti-chloropropyDphosphate, and the like.

The fuels frequently contain antioxidant additives such as 2,6-di-tert-butylphenol; 2,6-di-tert-butyl 4 methylphenol, 4,4 methylenebis(2,6 di-tert-butylphenol); 2,2 methylenebis(4-methyl-6-tert-butylphenol), phenylenediamines; p-nonylphenol; mixed alkylated phenols, 4,4-thiobis(3-methyl-6-tert-butylphenol), and the like.

Other materials can be present in the. fuel such as de-icers, metal deactivators, pour point depressants, boronesters, nickel alkyl phosphates and dyes.

The following examples illustrate the preparation of typical improved fuel compositions of this invention.

EXAMPLE 4 To a blending vessel is added 1000 gallons of a gasoline having the following properties:

Boiling range, F. 101-375 Research octane number 93 Aromatics (volume percent) 38 Olefinics (volume percent) 10 Aliphatics (volume percent) 52 To this gasoline is added a tetraethyllead antiknock agent containing two gram atoms of chlorine as ethylenedichloride per gram atom of lead and one gram atom of bromine as ethylenedibromide per gram of atom of lead. The quality of tetraethyllead antiknock agent added is sufficient to provide 3.17 grams of lead per gallon of fuel. There is then added sufficient 4,4'-benzylidene bis(2,6-di-tert-butylphenol)diacetate to give a concentration of 0.25 weight percent. There is then added 0.25 weight percent of cyclohexanone as an induction aid. The mixture is agitated until thoroughly mixed, resulting in a gasoline having reduced exhaust emission properties.

EXAMPLE 5 To a blending vessel is added 1000 gallons of a reformate gasoline having the following properties:

Boiling range, F. 94-403 Research octane number 97 Aromatics (volume percent) 62 Olefinics (volume percent) 5 Aliphatics (volume percent) 33 To this gasoline is added a tetramethyllead antiknock mixture containing one theory of chlorine as ethylenedichloride and 0.5 theory of bromine as ethylenedibromide. A quantity sufficient to provide 2.12 grams of lead per gallon is added. There is also added, as an antioxidant, a mixture of butylated phenols containing about 75 percent 2,6-di-tert-butylphenol, such that the gasoline contains 0.1 weight percent of the antioxidant mixture. Then 0.05 weight percent of 4,4'-(p-nonylbenzylidene)bis(2,6- di-tert-butylphenol) dioleate together with 1 percent of diethylene glycol diethyl ether is added and the mixture thoroughly stirred, resulting in a gasoline giving reduced emission and combustion chamber deposits weight when used to operate a spark ignition internal combustion engine.

Good results are also obtained in the above example when other benzylidene bisphenol acylates such as those previously listed are employed as the emission and deposit-reducing agent.

7 EXAMPLE 6 To a blending vessel its added 1000 gallons of a gasoline having the following properties:

Boiling range, F 103-399 Research octane number 89 Aromatics (volume percent) 21 Aliphatics (volume percent) 63 Olefins (volume percent) 16 To this gasoline is added an antiknock fluid as shown in Example 9 in quantities sufficient to give a lead concentration of 3.0 grams per gallon as tetraethyl lead. This addition concurrently adds 4,4'-benzylidene bis(2,6-ditert-butylphenol)diacetate in an amount equal to 0.05 weight percent.

EXAMPLE 7 To a blending vessel is added 1000 gallons of gasoline having the following properties:

Boiling range, F 98-410 Research octane 92 Motor octane 85 Aromatics (volume percent) 27 Aliphatics (volume percent) 66 Olefins (volume percent) 7 Sulfur, percent 0.05

To this gasoline is added 0.25 weight percent of a kerosene having a boiling range of 356-450 F., visc. at 1000 SUS of 73, flash point of 320 F., pour point 30 F., specific gravity 0.893, Conralson carbon of 0.02 weight percent and kauri-butanol No. of 28. There is then added 2.6 grams of lead per gallon as a mixture of lead alkyls having the approximate composition of 6.25 percent tetramethyl lead, 25 percent ethyltrimethyl lead, 37.5 percent diethyldimethyl lead, 25 percent methyltriethyl lead, and 6.25 percent tetraethyl lead. There is then added 0.3 theories of phosphorous as tricresyl phosphate. Following this is added 4,4'-benzylidene bis(2-methyl-6-seccetylphenol)di-n-butyrate in an amount equal to 0.5 weight percent of the mixture. The result is a gasoline having reduced emission-increasing and combustion chamber deposit-forming properties.

EXAMPLE 8 To a blending vessel is added 1000 gallons of a diesel fuel having a boiling range of from 430572 F., and a cetane number of 47. To this is added 0.3 weight percent amyl nitrate as a cetane improver. There is then added 0.2 weight percent of 4,4-benzylidene bis [2,6-di(umethylbenzyl)phenol]dipropionate, resulting in a diesel fuel having reduced exhaust emission and deposit forming properties.

In any of the previous examples, the forementioned emission-reducing compounds can be employed, giving fuels having reduced emission properties. Also, the concentrations may be varied from those shown. In general, a concentration of from about 0.01 to 3 weight percent of the emission-reducing additive can be employed. A preferred concentration range is from about 0.05 to about 1 weight percent, and a most useful range is from about 0.1 to 0.5 weight percent.

An especially useful means of adding the benzylidene bisphenol acylates to gasoline is to include them in the antiknock fluid concentrate which is normally added to gasoline so that the entire operation can be accomplished in a single blending step. These antiknock fluids contain an antiknock such as, but not limited to, tetraalkyl lead plus other materials which beneficially elfect the use of the antiknock. Especially useful tetraalkyl lead antiknocks are tetraethyl lead, tetramethyl lead, mixtures thereof, alkyl leads containing both ethyl and methyl groups, and mixtures thereof. These antiknock fluids usually contain a halogen compound as a scavenger. The most frequently employed halogen scavengers are ethylene dichloride and ethylene dibromide. The quantities of these scavengers can be varied within a wide range, but the best results are obtained when the antiknock fluid contains from 0.5 to 2 theories of chlorine as ethylene dichloride and from 0 to 1.0 theories of bromine as ethylene dibromide. A theory is equal to 2 gram equivalents of halogen per gram mole of lead. In other words, one theory of halogen is suflicient to convert the lead in a tetra-alkyl lead to lead dihalide.

An amount of -benzylidene bisphenol acylate is added to the anti-knock fluid such that when the antiknock fluid is added to gasoline in an amount sufficient to raise the octane number of the gasoline to the desired value there will also be included in the gasoline an emission and deposit reducing amount of the benzylidene bisphenol acylate. A preferred range of benzylidene bisphenol acylate concentration in the gasoline is from about 0.05 to 3 weight percent. Hence, a useful range of benzylidene bisphenol acylate in tetraalkyl lead antiknock fluids is from about 0.45 to 27.2 parts of the benzylidene bisphenol per part of lead as tetraalkyl lead. This amount will supply from 0.05 to 3 weight percent of the benzylidene bisphenol acylate when SllfilClCHt antiknock fluid is added to the gasoline to supply 3 grams of lead per gallon as tetraalkyl lead. When more or less lead is desired, the concentration range of benzylidene bisphenol acylate in the fluid can be varied accordingly to furnish the desired benzylidene bisphenol acylate concentration. Following are some representative examples of antiknock fluids containing exhaust and deposit reducing benzylidene bisphenol acylates.

EXAMPLE 9 An antiknock fluid is prepared by blending the following ingredients:

Parts Tetraethyllead 1000 Ethylene dibromide 290 Ethylene dichloride 306 4,4-benzylidene bis(2,6-di-tert-butylphenol) diacetate 290 Kerosene Orange dye 5 EXAMPLE 10 An antiknock fluid is prepared by blending the following ingredients:

Parts Tetramethyllead 1000 Ethylene dibromide 295 Trimethyl phosphate 4,4-(p-nonyl benzylidene)bis(2,6 di-sec-dodecylphenol)-di-butyrate 17,400

Kerosene 200 The above examples are merely illustrative of the typical antiknock fluids which can be prepared. Similar antiknock fluids can be prepared employing other antiknock agents such as triethylmethyllead, diethyldimethyllead, trimethylethyllead, tetravinyllead, triethylvinyllead, diethyldivinyllead, trivinylethyllead, ferrocene, methylferrocene, iron carbonyl, methylcyclopentadienyl manganese tricarbonyl, methylcyclopentadienyl nickel nitrosyl, N,N-dimethylaniline, and mixtures of any of the foregoing. Likewise, any of the previously described benzylidene bisphenol acylates can be employed in these antiknock fluids in quantities that will give the desired concentration in the final gasoline blend. These concentrations are easily determined by those experienced in blending additives in gasoline.

Tests have been conducted to demonstrate the useful exhaust emission properties of the present compounds. In these tests, a single cylinder overhead valve engine, having a 10:1 compression ratio and a 36 cubic inch displacement, was operated on a typical commercial gasoline containing 3.17 grams of lead as a commercial tetraethyl ead antiknock mixture containing one theory of chlorine as ethylenedichloride and 0.5 theory of bromine as ethylenedibromide. The engine was idled for 45 seconds and then run at 50 percent wide open throttle for 135 seconds under the following conditions.

Air/fuel ratio: 13 R.p.m.: 1370 Ignition timing: 15 B.T.C.

The above cycle was continuously repeated until both deposits and hydrocarbon emissions had stabilized. This usually required from about 100-145 hours of operation. The hydrocarbon content of the exhaust gas was determined using a Beckman 109-A Flame Isomerization Detector, and the deposits were determined by disassembling the engine, removing and weighing the deposits. The procedure was first carried out using a fuel without the emission reducing additive to obtain a baseline exhaust emission increase and then repeated on the same fuel containing an emission reducing additive. This was followed by another test on the fuel, again without the emission additive, to reconfirm the baseline. Using this procedure, the following results in terms of the percent reduction in exhaust hydrocarbon emission increase and total combustion chamber deposits were obtained using emission reducing additives of this invention.

Additive: 4,4 benzylidene (bis(2,6-di-tert-butylphenol) diacetate Conc.: 0.2

Reduction of emission increase: 62%

Reduction of deposit weight: 73%

As these results show, the emission-reducing additives of the present inventon effectively reduce both exhaust emission increase and engine deposits.

What is claimed is:

1. A combustion chamber deposit and exhaust emission reducing compound having the formula OJLR,

wherein R and R are independently selected from the group consisting of hydrocarbyl alkyl radicals containing from 1 to about 20 carbon atoms, aralkyl radicals containing from 7 to about 20 carbon atoms, mononuclear aryl radicals containings from 6 to about 20 carbon atoms and cycloalkyl radicals containing from to about carbon atoms; R R R and R are independently selected from the group consisting of hydrogen, hydrocarbyl alkyl radicals containing from 1 to about 20 carbon atoms, aralkyl radicals containing from 7 to about 20 carbon atoms, mononuclear aryl radicals containing from 6 to about 20 carbon atoms, and cycloalkyl radicals containing from 5 to about 20 carbon atoms, R is selected from the group consisting of hydrogen, hydrocarbyl alkyl radicals containing from 1 to about 20 carbon atoms, aralkyl radicals containing from 7 to about 20 carbon atoms, cycloalkyl radicals containing from 5 to about 20 carbon atoms and mononuclear aryl radicals containing from 6 to about 20 carbon atoms, and Z is selected from the group consisting of hydrogen and radicals having the formula:

wherein R is selected from the same group previously described for this radical.

2. The compound of claim 1 wherein R R R and R are tert-butyl radicals and R and R are bonded to the carbon atom of their respective benzene nuclei at the position ortho with respect to the carbon atom in said benzene nuclei bonded to oxygen; and R and R are hydrogen and Z is the radical:

and R is a hydrocarbyl alkyl radical containing from 1 to 20 carbon atoms.

3. The compound of claim 2 where R is the methyl radical.

4. A compound of claim 1 wherein R and R are independently selected from the group consisting of a-branched hydrocarbyl alkyl radicals containing from 3 to about 20 carbon atoms, u-branched aralkyl radicals containing from about 8 to about 20 carbon atoms, and cycloalkyl radicals containing from about 6 to about 20 carbon atoms, R and R are selected from the group consisting of hydrocarbyl alkyl radicals containing from one to about 20 carbon atoms, cycloalkyl radicals containing from 6 to about 20 carbon atoms, and aralkyl radicals containing from 7 to about 20 carbon atoms, R and R are H, Z is a radical having the formula:

wherein R is selected from hydrocarbyl alkyl radicals containing from 1 to about 20 carbon atoms.

5. A compound of claim 4 wherein R is selected from the group consisting of methyl, propyl, pentyl, undecyl,

' heptadecyl, and 9-heptadecenyl radicals.

6. A compound of claim 1 wherein R and R are tertbutyl radicals and R and R are selected from the group consisting of hydrogen and tert-butyl radicals, and R and R are hydrogen.

7. A compound of claim 6 wherein Z is a radical having the formula:

wherein R is a hydrocarbyl alkyl radical containing from 1 to about 20 carbon atoms.

8. A composition consisting substantially of benzylidene bis (butylated phenol) monoand di-n-butyrate which is produced by the process of (1) alkylating phenol with isobutylene to produce a mixture consisting substantially of dibutylated phenol,

(2) reacting said mixture with benzaldehyde to produce a benzylidene bis (butylated phenol) mixture, and

(3) butyrylating said benzylidene bis (butylated phenol).

9. A composition consisting substantially of benzylidene bis (monoand di-tert-butylphenol) diacetate which is produced by the process of reacting a monoand di-tertbutylphenol mixture with benzaldehyde to produce a benzylidene bis (monoand di-tert-butylphenol) mixture and acetylating said benzylidene bis (monoand di-tertbutylphenol) mixture.

References Cited UNITED STATES PATENTS 2,435,014 1/1948 Niederl 260-395 LORRAINE A. WEINBERGER, Primary Examiner L. A. THAXTON, Assistant Examiner US. Cl. X.R.

Po-ww UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5,5 LT,958 Dated Decemberl5, 1970 Invented Henry G. Braxton, Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line l i, after "emission" insert increase of Column 2, lines 21-25, formula 9 O H -C-R should read C-R- Column 2, line 31, "2,6-ditertbutyl" should read 2,6-di-te; butyl --5 line 33, "bis(o-secamylphenol) should read bis(osecamylphenol) Column 3, line 55, "benzaldeyhde" should read benzaldehyde Column 7, line 2, "its" shoulc read is Column 9, line 25, should be deleted before bis Column 10, line 5?, (Claim 8, line 9), insert "mixture" after phenol) iiaiimii) MD SEALED Aueat:

mull. .m. Anesting Offioer Gomlasionar of Patents 

